Measurements of spatiotemporal changes in G-actin concentration reveal its effect on stimulus-induced actin assembly and lamellipodium extension

Tai Kiuchi, Tomoaki Nagai, Kazumasa Ohashi, Kensaku Mizuno

    Research output: Contribution to journalArticlepeer-review

    57 Citations (Scopus)

    Abstract

    To understand the intracellular role of G-actin concentration in stimulus-induced actin assembly and lamellipodium extension during cell migration, we developed a novel technique for quantifying spatiotemporal changes in G-actin concentration in live cells, consisting of sequential measurements of fluorescent decay after photoactivation (FDAP) of Dronpa-labeled actin. Cytoplasmic G-actin concentrations decreased by ~40% immediately after cell stimulation and thereafter the cell area extended. The extent of stimulus-induced G-actin loss and cell extension correlated linearly with G-actin concentration in unstimulated cells, even at concentrations much higher than the critical concentration of actin filaments, indicating that cytoplasmic G-actin concentration is a critical parameter for determining the extent of stimulusinduced G-actin assembly and cell extension. Multipoint FDAP analysis revealed that G-actin concentration in lamellipodia was comparable to that in the cell body. We also assessed the cellular concentrations of free G-actin, profilin- and thymosin-β4-bound G-actin, and free barbed and pointed ends of actin filaments by model fitting of jasplakinolide-induced temporal changes in G-actin concentration.

    Original languageEnglish
    Pages (from-to)365-380
    Number of pages16
    JournalJournal of Cell Biology
    Volume193
    Issue number2
    DOIs
    Publication statusPublished - 2011 Apr 18

    ASJC Scopus subject areas

    • Cell Biology

    Fingerprint

    Dive into the research topics of 'Measurements of spatiotemporal changes in G-actin concentration reveal its effect on stimulus-induced actin assembly and lamellipodium extension'. Together they form a unique fingerprint.

    Cite this